POV is a brilliant tool once you get the hang of it. Admittedly, it took me a year of intentional practice to get it right. I had submitted what I thought was a fantastic fantasy vampire manuscript to an agent and she pointed out all the "head hopping". Rewriting that forced me to learn.
The way that I explain POV to writers I work with is by using a film analogy. The scene is the scene, what happens is what happens, but where you put the camera makes all the difference in the world. Consider a scene from your book and think of how it would be shot for a movie. Are you looking down on the action? Are you looking up at it? Are you seeing it from the perspective of a single person in the room?
POV is an opportunity to allow your audience to become intimate with your characters. To truly feel that connection, you want the audience to see the world through their eyes, thoughts, and emotional reactions. As the author, you control this by deciding whose perspective the story is being played out through.
I have a scene from a fantasy manuscript I am finishing that I'll use to demonstrate. It's an Arthurian Legend piece, where Merlin has been poisoned by his mother and is laying in bed in delirium. Initially we wrote the scene from the POV of Blaise, a priest from the Forest of Fire who is trying everything he can to heal Merlin. We initially saw the healing ritual through his eyes and his thoughts and his actions. Anything that happened in the room was interpreted by him. So when, in his stupor, Merlin cries for his sister Arianna, Blaise, not knowing who she is, has to interpret the meaning of the cries. The reader, like Blaise, becomes frustrated trying to communicate with Merlin who appears to be speaking gibberish.
Later, we went back and revisited the scene, writing it from Merlin's POV. Now we are putting the reader inside the delirium itself. The result is that the reader feels trapped inside Merlin’s poisoned mind as these phantoms chant over him and he goes from being lucid and hearing Blaise's prayer to heading off into the depths of the insanity caused by the poison.
Both options are relevant and both work. Both give the reader a different emotional experience. What does not work is flip-flopping back and forth sometimes being in Merlin's mind and sometimes in Blaise's. Less experienced writers take this omniscient POV and don't realize that they are preventing their reader from experiencing an intimate connection with their characters. Head hopping confuses readers because they are spending their time trying to stop the room from spinning instead of enjoying the story and being taken off into their own imagination.
If you really want readers to connect, you have to be very intentional about whose eyes they are seeing the story played out through.
I hope this is a decent starting point for the conversation. Ask more questions or make comments if you have them!